Color Measurements Research Articles

Quality of Sous Vide-Cooked Pork Loin Stored in Refrigerated Conditions

The sous vide cooking method offers advantage in preparing meat dishes in advance. This study aimed to evaluate the effect of refrigerated storage on the quality attributes of pork loin sous vide cooked under selected, optimised temperature and time parameters. Pork loin was cooked at varying temperatures (57–63 °C) and times (3.5–5.5 h), followed by refrigerated storage for up to 7 days. Analytical methods, including TBARS index for lipid oxidation, instrumental colour measurement, texture analysis, and volatile compound profiling, were used to assess changes in meat quality over time. The results indicated that heat treatment and storage time significantly influenced lipid oxidation, colour, and texture. The highest TBARS values were observed at higher cooking temperatures (61 °C and 63 °C), reflecting increased lipid oxidation. Colour changes were also temperature- and time-dependent, with a decrease in redness (a*) and an increase in lightness (L*) and yellowness (b*). Sensory evaluation revealed that juiciness, aroma intensity, tenderness, and flavour acceptability were strongly correlated with overall acceptability, while physical characteristics like colour and texture had a lesser impact. The study highlights the impact of sous vide cooking parameters on the quality and sensory attributes of pork loin, suggesting that optimised heat treatment can help preserve desirable meat characteristics during refrigerated storage.

Modeling the Rehydration Behavior of Oven and Vacuum Oven Dried Shrimp at Different Rehydration Temperatures and Determination of Quality Parameters

In this study, shrimps dried by oven (OD) and vacuum oven (VOD) in the previous study, were rehydrated at temperatures of 30, 40 and 50°C and the kinetics of rehydration during this time were examined and curves are modeled. In rehydration kinetic studies, rehydration contents, rehydration rates, moisture ratio and effective moisture diffusions were calculated. Modeling was done based on Peleg and Two-Term mathematical models from the obtained rehydration curve data, and the results were evaluated statistically using the reduced chi-square (χ2), coefficient of determination (R2) and root mean square error (RMSE) definitions. Color measurements were chosen as quality parameter analysis and interpretations were made based on the total color changes. When the results were examined, it was observed that all samples reached equilibrium in the 180 and 150 minute in oven drying and vacuum-oven drying, respectively and the sample with the highest rehydration value was observed in the one dried at 80°C in a vacuum-oven drying and rehydrated at 50°C. Since the drying time of the samples dried in the vacuum oven was shorter, their pores were less narrowed and thus they experienced more rehydration. It was observed that the samples were rehydrated more as the rehydration temperature increased. Since the rehydration rate, moisture content and effective moisture diffusivity values are in parallel with the rehydration contents the same increase occurred at these parameters. Looking at the mathematical modeling results, the Peleg model gave better results in samples rehydrated at 30 and 40°C, and the Two-Term model gave better results in samples rehydrated at 50°C. From the total color changes as expected vacuum-dried shrimps total color changes were less than the oven-dried shrimps and the color changes increased as the rehydration temperature increases due to the increase in the lightness values.

The effect of different polishing systems on the discoloration of composite resins: examples of commonly consumed beverages

Aims: The aim of this study is to evaluate the color stability of composite resin materials subjected to different polishing systems when exposed to commonly consumed beverages. Methods: In this study, four different composite polishing systems (Zenit, 3M Sof-Lex, Sofu, Kerr) and three types of beverages (Nescafé 3-in-1, Lipton tea bags, and distilled water) were used. A micro-hybrid resin composite (Tokuyama) was selected for the study. A total of 84 disk-shaped composite resin samples (8 mm in diameter and 2 mm thick) were prepared. The samples were divided into four main groups according to the polishing systems used, and further divided into three subgroups based on the beverage types, with seven samples in each subgroup, resulting in a total of 12 study groups. Initial color measurements, as well as measurements taken on days 1, 7, and 28, were recorded using a vita easyshade spectrophotometer. The data were tabulated and statistically analyzed using SPSS 25.0 software, employing one-way ANOVA and Tukey HSD post-hoc tests (p=0.05). Results: Examination of the 28-day staining results revealed a statistically significant difference between the results for distilled water and coffee, depending on the brand (p

Long-Term Evaluation of GCOM-C/SGLI Reflectance and Water Quality Products: Variability Among JAXA G-Portal and JASMES

The Global Change Observation Mission-Climate (GCOM-C) satellite, launched in December 2017, is equipped with the Second-generation Global Imager (SGLI) sensor, featuring a moderate spatial resolution of 250 m and 19 spectral bands, including the unique 380 nm band. After six years in orbit, a comprehensive evaluation of SGLI products and their temporal consistency is needed. Remote sensing reflectance (Rrs) is the primary product for monitoring water quality, forming the basis for deriving key oceanic constituents such as chlorophyll-a (Chla) and total suspended matter (TSM). The Japan Aerospace Exploration Agency (JAXA) provides Rrs products through two platforms, G-Portal and JASMES, each employing different atmospheric correction methodologies and assumptions. This study aims to evaluate the SGLI full-resolution Rrs products from G-Portal and JASMES at regional scales (Japan and East Asia) and assess G-Portal Rrs products globally between January 2018 and December 2023. The evaluation employs in situ matchups from NASA’s Aerosol Robotic Network-Ocean Color (AERONET-OC) and cruise measurements. We also assess the retrieval accuracy of two water quality indices, Chla and TSM. The AERONET-OC data analysis reveals that JASMES systematically underestimates Rrs values at shorter wavelengths, particularly at 412 nm. While the Rrs accuracy at 412 nm is relatively low, G-Portal’s Rrs products perform better than JASMES at shorter wavelengths, showing lower errors and stronger correlations with AERONET-OC data. Both G-Portal and JASMES show lower agreement with AERONET-OC and cruise datasets at shorter wavelengths but demonstrate improved agreement at longer wavelengths (530 nm, 565 nm, and 670 nm). JASMES generates approximately 12% more matchup data points than G-Portal, likely due to G-Portal’s stricter atmospheric correction thresholds that exclude pixels with high reflectance. In situ measurements indicate that G-Portal provides better overall agreement, particularly at lower Rrs magnitudes and Chla concentrations below 5 mg/m3. This evaluation underscores the complexities and challenges of atmospheric correction, particularly in optically complex coastal waters (Case 2 waters), which may require tailored atmospheric correction methods different from the standard approach. The assessment of temporal consistency and seasonal variations in Rrs data shows that both platforms effectively capture interannual trends and maintain temporal stability, particularly from the 490 nm band onward, underscoring the potential of SGLI data for long-term monitoring of coastal and oceanic environments.

Changes in optical properties of aesthetic paediatric restorative materials following exposure to beverages: In-vitro study.

Optical properties of recent aesthetic restorative materials must maintain an acceptable appearance throughout their functional lifetime. This study aimed to assess the changes in translucency and colour of recent resin-based restorative materials after exposure to beverages commonly consumed by children. An experimental in-vitro study on 48 discs specimens prepared from; Group I: Filtek Z250 XT (Nanohybrid), Group II: Cention N (Alkasite bulkfill), and Group III: SDR flow Plus (Flowable bulkfill). The prepared disc specimens were randomly assigned into 4 subgroups (n = 12) according to the immersion solution: Subgroup A (control): distilled water, B: Coca-Cola, C: chocolate milk, and D: Orange juice. Translucency and colour measurements were done before immersion (baseline) and on day 30 of exposure. Statistical analysis involved Two Way Repeated Measures ANOVA and Kruskal-Wallis test. The statistical analysis revealed that the restorative material, immersion time, and immersion solution had a significant effect on the change in translucency (p < 0.0001*, p < 0.0001*, p = 0.001*, respectively). Regarding colour changes, different immersion solutions had a statistically significant effect on Filtek Z250 XT and Cention N (p < 0.0001*). Distilled water and Coca-Cola were found to have a significant effect on colour change for all restorative materials investigated (p < 0.0001*, p = 0.003*). the optical properties of resin-based restorative materials used in paediatric dentistry were notably affected by prolonged exposure to beverages commonly consumed by children.

Effect of Staining and External Bleaching on the Color Stability and Surface Roughness of Universal-Shade Resin-Based Composite.

This study evaluated the color stability and surface roughness of two universal-shade compared to two nanohybrid composites after staining and external bleaching with 40% hydrogen peroxide. Two universal shade resin-based composites and two nanohybrid composites were tested. Twenty disc-shaped specimens from each material were fabricated and divided into two subgroups: one group was stained and bleached (staining group) and the other received bleaching treatment only (control group). The staining group was stained with coffee solution for 24h. Subsequently, each sample of all four materials was bleached using an in-office bleaching gel using 40% hydrogen peroxide. Color measurements were performed using a spectrophotometer to obtain the International Commission on Illumination parameters, L*; a*; and b* for each of the following periods: baseline, after bleaching, and two weeks after bleaching for the control group. The staining group was examined at baseline, after staining, after bleaching, and two weeks after bleaching. Surface roughness (Ra) of all the materials after each treatment step were also recorded. The data was statistically analyzed using SPSS 26.0 statistical software. Changes were considered statistically significant at P = 0.05. Descriptive statistics (means and standard deviations) were used to describe color measurements and surface-roughness values. Two-analysis of variance and one-way analysis of variance were used to compare the mean values of surface roughness, L*a*b*and ΔE00 values. Statistically significant differences and clinically acceptable ΔE00 were observed between all materials during the different stages in color measurements, whereas the surface roughness was significantly different for each study material and treatment mode. Staining with coffee solution and external bleaching produced acceptable color changes for all materials tested. Staining and bleaching increased the surface roughness values of the tested resin-based composites.

Update on tooth color measurement by visual and spectrophotometer methods

Introduction: Tooth colour assessment is a crucial aspect in aesthetic dentistry, as it influences the design of restorative and aesthetic treatments. There are various methods for assessing tooth colour, the most common being the visual method and the use of spectrophotometers. Each has advantages and disadvantages that can affect the accuracy and reproducibility of the results.Development: The visual method consists of comparing tooth colour with standardised shade guides. This approach is accessible and easy to implement, but its subjectivity can lead to variations in colour perception between different operators. Factors such as lighting, visual fatigue and environmental conditions can influence the assessment, compromising the consistency of the results. On the other hand, the spectrophotometer offers an objective measurement of tooth colour by quantifying the light reflected by the teeth at different wavelengths. This method provides accurate and repeatable data, eliminating the subjectivity of the visual method. However, its cost and the need for technical training can be limitations in its widespread use.Conclusions: Both methods have a significant role in tooth color assessment. While the visual method is more accessible and practical in clinical settings, the spectrophotometer offers superior accuracy and objectivity. The choice between the two will depend on the specific treatment needs and available resources. For optimal results, it is suggested to consider a combined approach that takes advantage of the strengths of each method.

Minimum Upper Bound Estimation With Colored Measurement Noise in the Presence of Generalized Unknown Disturbance

Minimum Upper Bound Estimation With Colored Measurement Noise in the Presence of Generalized Unknown Disturbance

Analysis of high-temperature exposure to physical changes in Valplast®-based denture with acrylic element for human identification purpose

BackgroundIdentification of victims will be difficult due to exposure to high temperatures when fires occur. In some cases of fire, small pieces, such as teeth, can be detached and ignored as necessary evidence. Destroyed body parts or the number of victims in a disaster makes the identification of victims more complicated, and forensic odontology is hoped to help the identification process. In a fire disaster, it is possible that a victim used dentures. One of them is a Valplast®-based denture with an acrylic element. If a victim wearing dentures caught fire and was exposed to high-temperature flames, there may be remains of dentures that can be identified. This study aimed to determine the physical changes in Valplast®-based dentures with acrylic elements in shape, color, and weight due to high exposure temperature. In this article, Valplast®-based dentures with acrylic element samples of four groups (P1: 32–288 °C; P2: 32–319 °C; P3: 32–412 °C; P4: 32–800 °C) were observed in shape, weight, and color measurements before and after heating using an oven.ResultsThe result is a change in shape and weight after heating that is shown by the results of the Kruskal–Wallis and Mann–Whitney tests with a p-value < 0.05, that is, the results of the one-way ANOVA test show that the average color change is not significantly different (p > 0.05).ConclusionValplast®-based dentures with acrylic elements experience changes in shape and weight after being heated at high temperatures. So, these results can be used as a reference in the forensic identification process for burn victims who use dentures.

Measurement of Seed Cotton Color Using RGB Imaging and Color-Unet

Color is a key indicator in evaluating seed cotton quality. Accurate and rapid detection of seed cotton color is essential for its storage, processing, and trade. In this study, an RGB imaging and semantic segmentation-based method was proposed for seed cotton color detection. First, a color detection system utilizing machine vision technology was developed to capture seed cotton images. Next, a Color-Unet model, incorporating convolutional block attention and improved inception E modules based on Unet, was applied to effectively remove impurities and shadows from the images, resolving the over-segmentation issue commonly encountered in traditional threshold segmentation. The results demonstrated that the pixel accuracy of segmentation reached 97.20%, the mean intersection over union was 91.81%, and the average segmentation speed was 322.3 ms per image. The Color-Unet model effectively addressed the over-segmentation problem. Subsequently, seed cotton color indexes were calculated using Hunter color formulas based on the segmented images. To evaluate the accuracy of color measurement obtained with the proposed method, a regression analysis was performed, comparing the results of those from the HX-410 measurement. The coefficient of determination of yellowness was 0.883, with a root mean square error of 0.150 and a mean relative error of 2.61%. The coefficient of determination of reflectance degree was 0.832, with a root mean square error of 1.56% and a mean relative error of 1.84%. The proposed method allows for the rapid and accurate assessment of seed cotton color from RGB images, providing a valuable technical reference for seed cotton color evaluation.

The Effect of Whitening and Daily Dentifrices on Red Wine Staining in Different Types of Composite Resins

Injectable resin composites offer flowability while providing enhanced mechanical properties, making them suitable for both posterior and anterior restorations. However, their susceptibility to discoloration and the efficacy of toothpaste in removing stains have not been extensively studied. This study aimed to evaluate the color stability of injectable (G-ænial Universal Injectable), flowable (3M™ Filtek™ Supreme Flowable, 3M, St. Paul, MN, USA), and conventional composite (3M™ Filtek™ Z350 XT Universal Restorative, 3M, MN, USA) after red wine exposure and to compare the stain removal efficacy of whitening (Colgate® Optic White™ Volcanic Mineral Whitening Toothpaste, Colgate-Palmolive, Chonburi, Thailand) versus daily (Colgate® Cavity Protection Toothpaste, Colgate-Palmolive, Chonburi, Thailand) dentifrice. Disc-shaped (7 mm in diameter and 2 mm in height) samples (n = 30) in A3 shade were prepared using injectable, flowable, and conventional composites. The samples were polymerized for 40 s on each side using a curing device set at 1500 mW/cm2 and immersed in red wine for 7 days. After staining, they were brushed with either whitening or daily dentifrice using 4950 strokes. Color measurements were taken at baseline (T1), after staining (T2), and after brushing (T3), using a spectrophotometer. Statistical analysis was performed using ANOVA. Results showed that conventional composites exhibited the highest color change (ΔET1-T2 = 5.50) compared to injectable (ΔET1-T2 = 3.60) and flowable composites (ΔET1-T2 = 3.36). While whitening dentifrice facilitated a greater recovery of discoloration in stained samples (ΔET1-T3 = 1.38–3.67) compared to daily dentifrice (ΔET1-T3 = 2.01–4.28), the observed difference was not statistically significant. In conclusion, all composite types are prone to staining from red wine, and both whitening and daily dentifrices show no difference in efficacy in reducing discoloration.

Evaluation of Tomato Landraces for Tolerance to Drought Stress Using Morphological and Physiological Traits

Drought is among the stress factors that, on a global scale, have direct negative effects on plant growth, yield, and quality. Great efforts are directed towards water shortage adaptation. Exploring the genetic diversity of landraces often tolerant to locally occurring stress can represent a valuable source for the development of cultivars with yield stability and improved quality under stress conditions. This study aimed to identify drought-tolerant tomato landraces based on an integrated approach involving morphological traits and physiological parameters. To investigate the effects of water deficit, five landraces and two controls were tested under optimum and 50% reduced irrigation. Yield and yield-related traits, color, firmness, and chlorophyll fluorescence measurements were evaluated. The summarized results indicated that the tomato landraces differed in their responses to water deficit. Water deficit decreased the yield by 44% and the average fruit weight by 29%. Physiological parameters were also significantly affected by water scarcity, with a decrease in the ratios Fv/Fm (the maximum quantum yield of PSII) and Fv/Fo (the maximum primary yield of photochemistry) of 8.2% and 35.5%, respectively, at 14 days’ exposure to stress. Landrace 1352, characterized by indeterminate growth habit and large, rounded, and red-colored fruits, showed a significantly lower reduction in yield and physiological parameters under reduced irrigation and could be used in breeding programs to develop new tomato lines combining resistance with quality.

Effects of Fluorescent Tracer Additives on PET During Material Recycling

ABSTRACTThe material properties and stable chemical structure of PET make it a frequently used polymer, for example, for packaging applications, and allow multiple recycling processes. Fluorescent tracer additives in polymer waste management may enhance the sorting quality of packaging waste streams by using the fluorescent signal of tracer additives introduced into the polymer matrix. Prior to field application of tracer additives, it is necessary to investigate tracer influence on the polymer matrix in general and, more specifically, in multiple recycling cycles. Therefore, PET with mineral tracer concentrations of 0, 10, 100, and 1000 ppm was extruded up to six times. To investigate changes in material properties, differential scanning calorimetry, intrinsic viscosity, spectroscopic analysis, tensile testing, and color measurements were performed. In parallel, the up‐conversion photoluminescence of the tracer was quantified. Polymer degradation is generally induced by mechanical and thermal degradation during multiple processing cycles, leading to chain shortening, reduction of molecular weight, and the formation of new functional groups, as previously published in the literature. The results of the experiments indicate that tracer additives do not further affect the thermal, rheological, chemical, and optical polymer properties. Moreover, photoluminescent tracer properties are not affected by multiple polymer processing cycles.

Instrumental Colorimetric Evaluation of Combined Enamel and Dentin Composite Resins Compared to the Vita Classic Shade Guide

Accurate color determination in dental restorations is crucial for achieving aesthetically pleasing and functional results. Traditionally, color selection has been performed using visual methods, which are subject to observer variability and factors such as lighting and experience. However, the use of instrumental technologies like spectrophotometry has allowed for greater objectivity and reproducibility in color measurement. This study aims to evaluate the accuracy of color determination in composite resin restorations using spectrophotometry, comparing the results obtained with the Vita Classic shade guide. A total of 120 samples were prepared using 4 types of composite resins and 3 enamel/dentin combinations (A2, A3, and A3.5), with 0.7 mm thickness for enamel and 1.3 mm for dentin, achieving a final thickness of 2 mm. Color measurements were taken with a Vita™ Easyshade® spectrophotometer, and the results were expressed in terms of ΔE using the CIE Lab* formula. Normality (Shapiro-Wilk) and homoscedasticity (Levene) tests were applied, and one-way ANOVA was used to assess differences between resin brands and shades. The results showed that, although no statistically significant differences were found in the A2 and A3 shades between brands, the A3.5 shade exhibited significant variations, with Filtek Z350 XT® 3M Espe Solventum being the resin that showed color values closest to the ideal.

Comparison spectral analysis and photometric parameters for different indoor and outdoor LEDs lighting

Light emitting diode (LED) lighting have gained in popularity owing to the advantages offered by them over incandescent lamps with respect to energy efficiency, strong robustness, operation life, and steadiness with time, making them suitable for a wide range of applications like residential and commercial lighting. In this work, the luminous flux and thermal stabilization time, color parameters, and spectral mismatch factors and their uncertainties have been measured and estimated for some indoor and outdoor commercial LED lamps of three different brands with nominal powers of 3, 9, and 36 watts. These lamps were classified into indoor-1, indoor-2, indoor-3, and outdoor LED lamps in order to enable the present analysis. The measurement methodology included a sophisticated luminous flux system using a 2.5-meter integrating sphere at the National Institute of Standards, NIS, equipped with the NIS photometer LMT U1000 and a series of NIS luminous flux secondary standard lamps calibrated at the National Physical Laboratory, NPL, in England. This is important for making proper, accurate measurements of the total luminous flux emitted by different LED lamps. In addition, an NIS Spectroradiometer (Ocean Optics HR 2000) and a photometric bench were used in order to measure the spectral power distribution of the lamps, by means of which we had the possibility to calculate the spectral mismatch correction factor quantify the color parameters and estimate the associated measurement uncertainties. The comprehensive approach in our study involves assessing luminous flux, thermal stabilization time, spectral mismatch correction factors, and chromaticity color coordinates, all in comparison to established standards provided by NIS Secondary Standard Lamps. This paper demonstrates that the obtained spectral mismatch correction factors and chromaticity color coordinates with their uncertainties can be used as basic corrections to luminous flux and color measurements. By doing this, the accuracy and dependability of these kinds of measurements are significantly improved, increasing the knowledge about the performance of LED lamps.

Color Masking Ability of Guided Enamel Regeneration with a Novel Self-Assembling Peptide and Resin Infiltration on Artificial Enamel Lesions Under Various Challenges: An In Vitro Spectrophotometric Analysis.

The color masking ability of resin infiltration (RI) and curodont repair fluoride plus-self-assembling peptide (CRFP-SAP) was investigated under various simulated oral challenging conditions. Sixty-four extracted caries-free human canines were randomly divided into two groups: Group 1 (RI) and Group 2 (CRFP-SAP). The baseline color values of samples were recorded using a spectrophotometer (VITA Easyshade® Advance 4.0 VITA Zahnfabrik, Bad Sackingen, Germany). The samples were stored in a demineralization solution for 4 days to induce artificial enamel lesions (AELs). The AELs of Groups I and II were treated with RI (Icon, DMG, Hamburg, Germany) and CRFP-SAP (vVARDIS, Zug, Switzerland), respectively, followed by color measurements. Each group was subjected to challenges such as remineralization, pH cycling, staining, and thermocycling, followed by color measurements. The difference between the mean ∆E (color difference value) of sound enamel and both treatment groups was less than 3.7 1-week post treatment. Meanwhile, the difference between the mean ∆E of RI-treated samples and all kinds of challenges was more than 3.7, while for the CRFP-SAP-treated samples, it was less than 3.7 for all kinds of challenges, except for the thermocycling, for which the mean ∆E difference was 4.3. RI and CRFP-SAP treatments were effective in masking the discoloration caused by AELs. However, the color was not stable for RI-treated samples, whereas it was stable for CRFP-SAP-treated samples under all challenges, except for thermocycling.

The Effects of CaO and MgO on Thermal, Mechanical and Optical Properties of Porcelain Tiles by Utilizing Blast Furnace Slag

In this study, the Blast Furnace Slag (BFS) of Zonguldak Eregli Iron and Steel Factories was used as a recycling raw material for the porcelain tile samples. A kind of clay with high MgO content was also used in the porcelain tile recipes. Maximum 10% of BFS was used instead of Na-feldspar. Sintering temperature for all samples was 1205°C for 50 minutes in the industrial roller kiln. Technological properties such as shrinkage, water absorption, colour measurement, and flexural strength were investigated as well as sintering properties and microstructures of the green and the sintered samples. As a result of the study, the addition of BFS did not adversely affect the technical properties of porcelain tile bodies. Particularly, the addition of BFS up to 3% contributed to an increase in flexural strength, and whiteness values of all samples increased because of the formation of anorthite and diopside compared to the reference body. The phase transformations and crystal formations such as anorthite and diopside resulted in a decrease in the firing shrinkage. Although the anorthite formation and diopside formation in the investigated samples had an adverse effect on condensation, it was found that they showed similar sintering behaviours compared to the reference body. This study showed that an industrial waste material can be converted into an environmentally friendly raw material that can create added value and provide energy efficiency.

Determination of Physical-Mechanical Properties of Leek Plant (Allium porrum L.)

Leek is a vegetable grown towards the end of summer and harvested during fall, found commonly in Asian diet and grown commonly throughout the world. Consumed both fresh and dry, mechanical properties of leek plant need to be well-known with regards to the studies related to it’s production, processing, packaging, transport and agricultural mechanization applications. The purpose of this study is to define the physical and mechanical properties of leek plant (Allium porrum L.) used for agricultural purposes in Turkey. Conducted with different types of knifes (smooth, serrated) and different shearing angles (30, 45, 60°), shearing force, bio-yield force, rupture force, energy in rupture force, deformation, shearing stress, stress in rupture force, stiffness values have been determined for 3 different sections of leek plant. Furthermore, colour measurements have been performed for each section of leek plan at 3 different heights. The highest shearing, bioyield force and rupture force values have been defined respectively as 66.27±3.52, 53.02±2.82 and 48.15±33.71 N during the shearing made with a smooth knife. Highest consumed energy value has been defined as 1.10±0.09 J in the studies conducted with smooth knife while the lowest value has been defined as 0.23±0.12 J in the studies carried out with serrated knife. The lowest deformation value has been defined as 25.37±1.18 mm in the experiments performed at 45° knife angle with a serrated knife.

Cartographic Visualisation of Light Pollution Measurements

The light pollution of the night sky is already a widespread phenomenon, the spatial extent and magnitude of which are increasingly represented in the form of thematic maps and cartographic visualization. Its leading cause needs to be correctly designed or adequately installed outdoor lighting. The problem of excessive artificial light emission at night, together with its adverse effects, has already reached such a level that it has become necessary to develop usable and comprehensible methods for the cartographic representation of the distribution of the phenomenon. In practice, there are several ways to measure the intensity of this pollution. However, there are no uniform legal standards for the use of outdoor lighting and no guidance and guidelines for the visualization of measurement data. Such visualization should provide a consistent, reliable, and, above all, readable picture of the phenomenon adapted to the needs of different audiences. Examples of the representation of the results of measurements of light pollution of the night sky can be found in the literature or a few atlases. Still, they often differ in color scales, value divisions, and measurement units used. This paper reviews the scales and units available in the literature to describe this phenomenon. The differences between the approaches of specialists from different branches and their influence on the final interpretation of the data are also presented. In addition, an authorial solution is proposed to standardize methods of cartographic visualization of the spatial distribution of light smog measurement results. The article attempts to draw attention to the importance of the graphical description of light smog, which will shortly be the subject of increasing research and work on the unification of cartographic communication.

Parchment preservation state of the Prayer book of Mary of Guelders

Illuminated medieval manuscripts are of outstanding value and their preservation is of great importance, not only because of their beauty but also because of the information they contain about medieval society. This work focuses on the evaluation of the parchment's state of preservation of the Prayer book of Mary of Guelders, which comprises about 600 folios. The knowledge gained should support the decision-making process regarding suitable conservation measures. An assessment of the preservation state of the parchment was performed from the macro- down to the microscale. Optical observations of cracks in the parchment and colour measurements preceded chemical analyses. The hydrothermal stability of the fibres was evaluated by means of observations using a micro hot table (MHT). The chemical state of preservation of parchment was evaluated using Laboratory-based Fourier transform (FT) Infrared (IR) analysis in reflection mode as well as synchrotron FTIR imaging in transmission mode at the IRIS beamline at BESSY II/ HZB in Berlin. The study allowed the conclusion that the parchment of the Prayer book of Mary of Guelders was in good state of preservation and indicated that the parchment changes were mainly caused by mechanical stress on the folios due to tight binding of the book and not by chemical processes.